The olfactory system is relatively simple in comparison to the visual and auditory systems. Though it is less important for sensation in man than in other mammals its function is a fundamental determinant of behavior in most vertebrates. It consists of a surface array of receptors, which are differentially sensitive to odors, connected in series to two neuronal surfaces: the olfactory bulb and the olfactory cortex. Odors are encoded as a space-time pattern of discharge on the axons of the receptors. These patterns are transformed as they are transmitted through the bulb and then the cortex into the basal forebrain. The immediate object of this study is the analysis and measurement of the neuronal pattern transformations, which constitute the "functions" of the bulb and cortex, and the interpretation of these processes in terms of the physicochemical properties of the component neurons. The long-term goal is the analysis of how the neurons in the bulb and cortex perform in relation to the behavioral phenomena of perception, motivation, attention and decision making.